I bought Harris's book and the Australian model boiler standards. I then re-drew the Harris vertical multitube using the Australian standards (redrawing the Harris picture let me work out where to put the fittings anyway). This covered issues such as the actual size of bushes and tube spacing – I reckon i would have been better off with a smaller number of tubes at larger spacing, except that the flue needs to be warm to get a proper draw on a spirit burner – all good experience)
The reading/drawing process probably taught me more about the subject than I would have ever achieved following a set of plans straight off and really only took 2 evenings with compass and set square – the standards are very well written. They also resulted in a tool list – and then a set of ME taps and dies which is always good.
This was a 3" – to small for your task, but the concept holds
Have you thought about doing a small (2 1/2 or 3"
to get the feel for heat management on big chunks of copper when silver soldering, and to think about things like a hearth? pretty cheap to do and useful to make your smaller engines sound right when showing off to family. (its a regular activity in the shed when we have visitors)
Edited By David Paterson 4 on 31/05/2017 02:22:07